Serum Levels Of Soluble CD26 And CD30 And Their Clinical Significance In Patients With Primary Immune Thrombocytopenia

Background:Primary immune thrombocytopenia (ITP), previously also known as idiopathic thrombocytopenic purpura, is a relatively common blood disorder characterized by autoimmune-mediated platelet destruction and suboptimal inadequate platelet produced by megakaryocyte. CD26 and CD30 are glycoprotein molecules used as a Thl and Th2 cell marker respectively, of which sCD30 and sCD26 are separately their two kinds of soluble form.sCD30 and sCD26 respectively indicate the immune response mediated by Th2 and Thl cells. Previous studies have showed that there are T cell immune abnormalities in ITP and one of the main manifestations of Th1/Th2 ratio imbalance. Recent reports have found the clinical significance of sCD30 and sCD26 in several autoimmune diseases including rheumatoid arthritis and systemic lupus erythematosus. These results suggest that the serum levels of sCD30 and sCD26 may also be correlated with disease activity/severity in patients with primary immune thrombocytopenia, however, the specific relationship is still unknown.Objective:The present study was aimed to investigate the associations between the levels of sCD30 and sCD26 and the disease activity so as to evaluate their value in ITP patients.Methods:We enrolled 47 ITP patients, of which including 23 active ITP patients and 24 patients in remission, and 20 healthy controls. (1) Peripheral blood samples from patients with ITP, and healthy persons were centrifuged and plasma was obtained and stored at -80℃ until it was assayed. Peripheral blood mononuclear cells (PBMCs) were separated by density gradient centrifugation using Ficoll-Hypaque gradients centrifugation. (2) Total RNA of the isolated PBMCs was isolated by TRIzol reagent and converted to cDNA. (3) The mRNA expression of CD30 was quantified by RT-PCR using SYBR Green as a double-strand DNA-specific binding dye on an ABI-7500 Sequence Detection System. (4) The concentrations of sCD30 and sCD26 in the peripheral blood plasma were measured by ELISA.Results:1. The concentrations of sCD30 were significantly higher in active ITP patients (42.18 ng/ml) than in patients in remission (28.99 ng/ml, P=0.021)and in healthy controls (27.10 ng/ml, P=0.002), but remission patients and healthy controls (P=0.689) did not significantly differ in the concentrations of sCD30.2. Healthy controls (1079.11 ng/ml) had significantly higher plasma sCD26 levels than did in remission (750.77ng/ml, P=0.004). No significant difference was found in plasma sCD26 levels among healthy controls and ITP patients in active disease (876.83 ng/ml, P=0.072). Similar results also occurred among patients in remission and active ITP patients (P=0.237).3. The ratios of sCD26/sCD30 in healthy controls were increased significantly compared with ITP patients with active disease (P=0.005), while no significant difference was found in ratios of sCD26/sCD30 among healthy controls and ITP patients in remission (P=0.198). And the same situation was also found among patients in remission and active ITP patients (P=0.093).4. However, there was no significant difference in the mRNA expression of CD30 in PBMCs among ITP patients with active disease, patients in remission and healthy controls (P>0.05).5. Correlations between the platelet levels and the plasma sCD26 and sCD30 concentrations and the ratios of sCD26/sCD30 were analyzed in active ITP patients. The data showed there were no correlations between platelet levels and plasma sCD26 (r=0.304, P=0.159), plasma sCD30 (r=0.018,P=0.936)and ratios of sCD26/sCD30 (r=0.330, P=0.124).Also there is no correlation between the plasma sCD30 and the sCD26 concentrations (r=-0.082, P=0.711).6. Our data shows that there’s no correlation between the concentrations of sCD30 and course of disease (r=-0.021, P=0.926), neither are between the concentrations of sCD26 and course of disease (r=-0.197, P=0.368), the sCD26/sCD30 ratios and the course of disease (r=-0.011, P=0.959)in the plasma of active ITP patients.7. Interesting, there is a positive correlation in active ITP patients between the concentrations of sCD30 and hemorrhage (r=0.493, P=0.017), but not between plasma sCD26 levels and hemorrhage (r=-0.064, P=0.773) and ratios of sCD26/sCD30 and hemorrhage (r=-0.381, P=0.073).8. Additionally, the plasma sCD26 and sCD30 concentrations were both reduced after effective treatment.Conclusion:In summary, our data suggest that the concentrations of sCD30 and sCD26/sCD30 in the peripheral blood plasma of ITP patients may contribute to reflecting the disease activity. However, sCD26 did not have the same effect. And the function may have a certain correlation with the abnormal Th1/Th2 polarization. The levels of sCD30 in plasma may be a useful indicator to evaluate patients’ response to treatment.